1. Field of the Invention
The present invention relates to solid-state imaging devices for capturing images and producing image signals by means of a plurality of photoelectric conversion elements and also to driving methods for driving such imaging devices. More particularly the present invention relates to a solid-state imaging device which performs an addition operation on pixel data and then outputs the result, and to a driving method therefor.
2. Description of the Related Art
In general, driving modes for an image sensor includes an all-image readout mode in which all pixels are read out for normal applications and a low-resolution readout mode in which pixels are read out at a low resolution for high frame rate applications. In the mode for high frame rate applications, data rate is effectively reduced by skipping pixels, but aliasing noise is undesirably increased at the same time due to low sampling frequency. To reduce the aliasing noise, there is a known method of adding and averaging signals of adjacent pixels instead of skipping pixels in the course of readout (See, for example, Japanese Unexamined Patent Application Publication No. 2004-356791).